Apparatus for barrel-plating small articles



Get. 9, 1956 'w, LUTHER 2,766,201

APPARATUS FOR BARREL-PLATING SMALL ARTICLES Filed June 12 195s 1N VEN TOR. EDGAR W LU THER Arron/var APPARATUS FOR BL-PLATIN G SMALL ARTICLES Edgar W. Luther, Hartford, Conn, assignor to Underwood Corporation, New York, N. Y., a corporation of Delaware Application June 12, 1953, Serial No. 361,125

4 Claims. (Cl. 204213) This invention relates to electroplating, and is concerned with means whereby comparatively small batches of small articles may be plated economically and easily while using conventional barrel-plating processes, even though the batches or the articles themselves are smaller than could be barrelplated readily in the ordinary way.

'In barrel-plating small articles, it is now customary to place a considerable number of the articles or parts to be plated within a porous tumbling-barrel or drum, the drum with the contained parts being rotated within a plating solution or electrolyte to which a plating current is supplied by means of electrodes, one or more cathodes in contact with the articles being plated and an anode immersed in the electrolyte. As the drum is rotated, an even deposit of plating is gradually built up on the parts, and when the plating has reached the desired thickness, the articles are removed from the solution and from the drum, and are washed and dried, or may be treated other wise for subsequent use. As long as all the articles in the drum are of a single size and character, such known apparatus and process as described above is very satisfactory in large quantity production plating of such articles. However, if batches of two articles of dissimilar character are to be plated according to known techniques, these batches of articles must be plated separately from each other. Otherwise the parts will become mixed by random movement and loose confinement during the tumbling and plating and will require considerable additional time and labor for sorting and separating after plating. If one of the parts is of extremely small size, there is the additional hazard that the perforations or screening for admitting the electrolyte in a certain plating barrel may not be small enough to retain the part within the drum, and consequently a barrel must be found with smaller openings. Obviously, if batches of more than two kinds of parts are involved, the sorting complications increase. Frequently, also, the number of parts in one of the batches to be plated may be so small that it would be uneconomical to operate a plating drum for that batch alone. Furthermore, if a batch is below a given volume for a certain plating drum, it may become impossible for plating to be accomplished satisfactorily, because the loosely confined parts will not have sufiicient electrical contact with the plating cathodes during the random tumbling movement.

The present invention is directed toward a device to overcome all these difficulties in plating small batches of small parts, and to make it possible to barrel-plate economically and etficiently two or more dissimilar batches of parts at the same time without requiring later tedious separating of the different kinds of plated parts.

In carrying out the objects of this invention, in one embodiment thereof, a porous auxiliary container is provided for separately carrying small batches of articles to be plated within a conventional plating drum, and electrical paths are provided through the container so that the cathode current in a batch of articles in the drum outside of the container will reach articles within the con- 2,766,201 Patented Oct. 9, 1956 tainer. Because of the porous nature of the container and by means of the electrical paths, the plating will be performed simultaneously on both batches, although they will be kept separated from each other so that they may be sorted readily after plating is complete. Time, labor, and consequent cost are thereby saved.

Further objects and advantages of the invention will be clarified by the following description and claims, together with the accompanying drawing in which is 1'1- lustrated one example of an arrangement embodying the present invention and utilizing the auxiliary container.

In the drawing:

Figure 1 is a semi-diagrammatic sectional view through the side of a conventional plating tank, with the usual loaded plating barrel and electrodes, and indicating small auxiliary containers within the barrel; and

Figure 2 is a side view, on a larger scale, of one form of an auxiliary container of the present invention, parts being broken away for clarity in illustration.

The plating barrel or drum 3 has the usual perforations 4- in its walls, which admit plating solution or electrolyte 5 from the plating tank 6 in which the drum is immersed. The drum is rotated about an axis 7 by any suitable means (not shown) so that the batch of parts or articles 8 loosely confined in the drum are tumbled in the customary fashion for plating. The broken line d indicates the approximate level of loading of the batch of parts 8 in the drum. Plating current is supplied from a suitable direct current power source such as the battery 10 to the electrodes in the tank, lead 11 being connected to an anode 12 which is in the solution, and leads 1 3 being connected to cathodes 14 which are on the drum and make electrical contact with the batch of parts 8 as the parts are tumbled. The above is conventional construction and need not be further described, excepting to note that there are many types or styles of barrel-plating devices and that the present invention may be used with any of these where it is desired to plate batches of more than one kind of article simultaneously in the same plating tumbling drum.

Before or during the plating of a batch of parts in an apparatus as above described, the present invention may be used to add another batch of parts to the same drum while keeping the two batches separated. This is accomplished by an auxiliary container 1'5, small enough to be inserted and loosely confined with the main batch of parts in the plating drum, but large enough or of such shape that it will not be confused with the parts 8 already in the drum. The shape of this container is shown as spherical (a ball) because this configuration lends itself to uniformity in action regardless of its position in the barrel. Obviously other shapes of containers might be used to gain much the same results, as long as the remaining requirements are met.

The walls of container 15 must be porous, so that the plating solution may freely pass through, and for this purpose a series of small holes 16 are provided in the container walls. These holes are made large enough and of sutficient number so that the plating solution can at all times reach the batch of metallic articles 17 in the container, but at the same time are small enough so that the articles 17 will not fall out of or become stuck in the openings. In order to load and unload the container, means are provided for opening and closing the same, and in the drawing this takes the form of a threaded joint 13 between one half 19 of the container and the other half 20.

The walls of the container may be made entirely of metal to provide a conducting path to parts within. However, it is preferred to use an insulating substance or dielectric not substantially affected by the plating current, the electrolyte, or the physical tumbling action. Plastics such as Bakelite and Lucite have been found to be suitable materials for the container walls.

When the walls of the container are made of electrical insulating material as above described, means are. provided on the container itself to conduct the plating current from the batch of articles in the drum outside of the auxiliary container to the batch of articles within the container. This may take the form of a multiplicity of metallic electrodes 21, threaded as at 22 through appropriate holes in the walls of the ball, with radially extending inner ends 23 for contact with the articles 17 and with enlarged protruding outer heads 24 for contact with the batch of articles 8 in the drum.

Because of the random positions which the container will take with respect to the main load of articles within the drum during the tumbling process, it is important that the heads of the electrodes 21 and their inner extensions be fixedly secured in substantially uniformly spaced relation to each other throughout the entire surface of the container. This is done so that, regardless of the position of the container, one or more of the electrodes always will be in contact at the same time with both the main batch of parts in the drum and the smaller batch in the container.

In use, the plating drum is loaded in the usual way with a batch of metallic parts to be plated, and a proper plating solution is supplied to the tank. Electrolytes for plating copper, cadmium, nickel, tin, and silver have all been found to perform satisfactorily, Plating current is applied to the main electrodes. When it is desired to plate a small batch of other small metallic articles, an auxiliary container according to this invention is loaded with such other articles, the container is closed, and the loaded container is placed with the first batch of parts in the drum. Plating of both batches will proceed as the drum is rotated, the auxiliary container obtaining necessary plating solution through the holes 16 and being supplied with necessary plating current through electrodes 21 from the cathodes 14 of the drum and from the batch of parts 8 in contact with these cathodes. When plating is complete, the parts 8 and the container 15 are removed from the plating tank, and the container may be readily identified and separated from the parts 8. Thereafter, the parts 17 may be unloaded from the container without need of sorting, and processed or used in any desired fashion. Naturally, there is no need to limit the procedure to a single auxiliary container, if more than one additional batch of parts is desired to be plated. Figure l of the drawing shows three auxiliary containers within the drum, and there may be more or less than this number and they may be of different sizes or shapes from each other and hold several kinds of parts different from each other and from the main batch.

The articles in the batch or load within an auxiliary container, instead of being identical to each other as implied above, might be sets of dissimilar parts which it is desirable to keep together for future assembly or use.

As will be evident from the foregoing description, certain aspects of this invention are not limited to the particular details of construction of the example illustrated, and it is contemplated that various and other modifications and applications of the invention will occur to those skilled in the art. It is therefore intended that the appended claims shall cover uch modifications and applications as do not depart from the true spirit and scope of this invention.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. In electroplating equipment for use in a process wherein a tumbling drum contains an electrolyte and has cathode means, and a first batch of metallic articles is loosely confined and tumbled in the electrolyte in said drum in contact with said cathode means for plating, the combination with said drum of an auxiliary container loosely confined in the drum for tumbling together with said first batch of articles in said electrolyte in contact with said cathode means, said container comprising a body having porous walls of dielectric material for passage of electrolyte therethrough, said walls defining an outer surface and enclosing a hollow interior for loosely confining a second batch of articles, a multiplicity of separate electrically conducting elements fixed to and passing through said walls from the outer surface of said body adjacent the first batch of articles, into said hollow interior adjacent the second batch of articles, said conducting elements being held substantially uniformly spaced throughout the entire outer surface and interior of said body, and means for opening said body, whereby the second batch of articles may be inserted or withdrawn from said container and whereby said first and second batches are separated from each other although plated together in said drum.

2. In barrel-plating equipment for use in a process wherein a rotating plating drum contains an electrolyte and main plating electrodes in the electrolyte, and a first batch of metallic articles is loosely confined and tumbled in the electrolyte in said drum in contact with said main electrodes for plating, the combination with said drum of an auxiliary container loosely confined in the drum for tumbling together with said first batch of articles in said electrolyte in contact with said electrodes, said container comprising a body of dielectric material composed of a plurality of parts removably secured together, said parts when secured defining an outer surface and enclosing a hollow interior loosely confining a second batch of articles, fluid-carrying passageways in said body for passage of the electrolyte between said outer surface and said interior, a multiplicity of auxiliary metallic electrodes secured to said body, each electrode extending outwardly at one end from the outer surface of the body toward the first batch of articles in said drum and extending inwardly at the other end into said hollow interior toward the second batch of articles in said container, said auxiliary electrodes being located to protrude at intervals spaced from each other throughout substantially the entire outer surface and interior of said container body, said body, when its parts are separated, permitting articles of said second batch to be inserted into or withdrawn from said interior.

3. In barrel-plating equipment for use in a process wherein a plating drum contains an electrolyte and electrodes and a main load of metallic pieces is loosely confined and tumbled in the electrolyte in contact with said electrodes in said drum for plating, the combination with said equipment drum of an auxiliary container for plating a small batch of metallic pieces which it is desired to keep separate from the main load of pieces in said drum, said container being loosely confined in the drum for tumbling together with said main load in said electrolyte in contact with the electrodes, and comprising a hollow body of electrical insulating material adapted to hold metallic pieces to be kept separate from the main load, a porous wall on said body for permitting fiow of the electrolyte therethrough, metallic electrically conducting members supported by and passing through the wall of said body, heads on said members protruding outside of said body, and inner ends on said members extending inside the hollow of said body.

4. In electroplating equipment for use in a process wherein a tumbling drum contains a plating solution and cathode means, and a main batch of articles is loosely confined and tumbled in the solution in said drum in contact with said cathode means for plating, the combination with said equipment drum of an auxiliary container for a second batch of articles to be plated, said container being loosely confined in the drum for random tumbling movement therein together with said main batch in said plating solution in contact with the cathode means, and said container comprising a hollow ball adapted to be opened for receiving articles of said second batch, said References Cited in the file of this patent UNITED STATES PATENTS Moneuse et al July 27, 1869 Merrit Mar. 30, 1920 FOREIGN PATENTS Great Britain Mar. 8, 1934 Great Britain Aug. 2, 1906 

1. IN ELECTROPLATING EQUIPMENT FOR USE IN A PROCESS WHEREIN A TUMBLING DRUM CONTAINS AN ELECTROYLTE AND HAS CATHODE MEANS, AND A FIRST BATCH OF METALLIC ARTICLES IS LOOSELY CONFINED AND TUMBLED IN THE ELECTROLYTE IN SAID DRUM IN CONTACT WITH SAID CATHODE MEANS FOR PLATING, THE COMBINATION WITH SAID DRUM OF AN AUXILIARY CONTAINER LOOSELY CONFINED IN THE DRUM FOR TUMBLING TOGETHER WITH SAID FIRST BATCH OF ARTICLES IN SAID ELECTROLYTE IN CONTACT WITH SAID CATHODE MEANS, SAID CONTAINER COMPRISING A BODY HAVING POROUS WALLS OF DIELECTRIC MATERIAL FOR PASSAGE OF ELECTROLYTE THERETHROUGH, SAID WALLS DEFINING AN OUTER SURFACE AND ENCLOSING A HOLLOW INTERIOR FOR LOOSELY CONFINING A SECOND BATCH OF ARTICLES, A MULTIPLICITY OF SEPARATE ELECTRICALLY CONDUCTING ELEMENTS FIXED TO AND PASSING THROUGH SAID WALLS FROM THE OUTER SURFACE OF SAID BODY ADJACENT THE FIRST BATCH OF ARTICLES, INTO SAID HOLLOW INTERIOR ADJACENT THE SECOND BATCH OF ARTICLES, SAID CONDUCTING ELEMENTS BEING HELD SUBSTANTIALLY UNIFORMLY SPACED THROUGHOUT THE ENTIRE OUTER SURFACE AND INTERIOR OF SAID BODY, AND MEANS FOR OPENING SAID BODY, WHEREBY THE SECOND BATCH OF ARTICLES MAY BE INSERTED OR WITHDRAWN FROM SAID CONTAINER AND WHEREBY SAID FRIST AND SECOND BATCHES ARE SEPARATED FROM EACH OTHER ALTHOUGH PLATED TOGETHER IN SAID DRUM. 